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    <script>
        function add(...args) {
            let num = 0
            num = args.reduce((p, c) => p + c, num)
            const temp = function (...args) {
                num = args.reduce((p, c) => p + c, num)
                return temp
            }
            temp.toString = function () {
                return num
            }
            return temp
        }
        alert(add(1, 2)(2, 2)(3, 2)(1))
        alert(add(1, 2)(3))
    </script>
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